half-past nine on the following morning found us spinning along the albert embankment in a hansom to the pleasant tinkle of the horse's bell. thorndyke appeared to be in high spirits, though the full enjoyment of the matutinal pipe precluded fluent conversation. as a precaution, he had put my notebook in his pocket before starting, and once or twice he took it out and looked over its pages; but he made no reference to the object of our quest, and the few remarks that he uttered would have indicated that his thoughts were occupied with other matters.

arrived at vauxhall station, we alighted and forthwith made our way to the bridge that spans upper kennington lane near its junction with harleyford road.

"here is our starting point," said thorndyke. "from this place to the house is about three hundred yards—say four hundred and twenty paces—and at about two hundred paces we ought to reach our patch of new road-metal. now, are you ready? if we keep step we shall average our stride."

we started together at a good pace, stepping out with military regularity and counting aloud as we went. as we told out the hundred and ninety-fourth pace i observed thorndyke nod towards the roadway a little ahead, and, looking at it attentively as we approached, it was easy to see by the regularity of surface and lighter colour, that it had recently been re-metalled.

having counted out the four hundred and twenty paces, we halted, and thorndyke turned to me with a smile of triumph.

"not a bad estimate, jervis," said he. "that will be your house if i am not much mistaken. there is no other mews or private roadway in sight."

he pointed to a narrow turning some dozen yards ahead, apparently the entrance to a mews or yard and closed by a pair of massive wooden gates.

"yes," i answered, "there can be no doubt that this is the place; but, by jove!" i added, as we drew nearer, "the nest is empty! do you see?"

i pointed to a bill that was stuck on the gate, bearing, as i could see at this distance, the inscription "to let."

"here is a new and startling, if not altogether unexpected, development," said thorndyke, as we stood gazing at the bill; which set forth that "these premises, including stabling and workshops," were "to be let on lease or otherwise," and referred inquiries to messrs. ryebody brothers, house-agents and valuers, upper kennington lane. "the question is, should we make a few inquiries of the agent, or should we get the keys and have a look at the inside of the house? i am inclined to do both, and the latter first, if messrs. ryebody brothers will trust us with the keys."

we proceeded up the lane to the address given, and, entering the office, thorndyke made his request—somewhat to the surprise of the clerk; for thorndyke was not quite the kind of person whom one naturally associates with stabling and workshops. however, there was no difficulty, but as the clerk sorted out the keys from a bunch hanging from a hook, he remarked:

"i expect you will find the place in a rather dirty and neglected condition. the house has not been cleaned yet; it is just as it was left when the brokers took away the furniture."

"was the last tenant sold up, then?" thorndyke asked.

"oh, no. he had to leave rather unexpectedly to take up some business in germany."

"i hope he paid his rent," said thorndyke.

"oh, yes. trust us for that. but i should say that mr. weiss—that was his name—was a man of some means. he seemed to have plenty of money, though he always paid in notes. i don't fancy he had a banking account in this country. he hadn't been here more than about six or seven months and i imagine he didn't know many people in england, as he paid us a cash deposit in lieu of references when he first came."

"i think you said his name was weiss. it wouldn't be h. weiss by any chance?"

"i believe it was. but i can soon tell you." he opened a drawer and consulted what looked like a book of receipt forms. "yes; h weiss. do you know him, sir?"

"i knew a mr. h. weiss some years ago. he came from bremen, i remember."

"this mr. weiss has gone back to hamburg," the clerk observed.

"ah," said thorndyke, "then it would seem not to be the same. my acquaintance was a fair man with a beard and a decidedly red nose and he wore spectacles."

"that's the man. you've described him exactly," said the clerk, who was apparently rather easily satisfied in the matter of description.

"dear me," said thorndyke; "what a small world it is. do you happen to have a note of his address in hamburg?"

"i haven't," the clerk replied. "you see we've done with him, having got the rent, though the house is not actually surrendered yet. mr weiss's housekeeper still has the front-door key. she doesn't start for hamburg for a week or so, and meanwhile she keeps the key so that she can call every day and see if there are any letters."

"indeed," said thorndyke. "i wonder if he still has the same housekeeper."

"this lady is a german," replied the clerk, "with a regular jaw-twisting name. sounded like shallybang."

"schallibaum. that is the lady. a fair woman with hardly any eyebrows and a pronounced cast in the left eye."

"now that's very curious, sir," said the clerk. "it's the same name, and this is a fair woman with remarkably thin eyebrows, i remember, now that you mention it. but it can't be the same person. i have only seen her a few times and then only just for a minute or so; but i'm quite certain she had no cast in her eye. so, you see, sir, she can't be the same person. you can dye your hair or you can wear a wig or you can paint your face; but a squint is a squint. there's no faking a swivel eye."

thorndyke laughed softly. "i suppose not; unless, perhaps, some one might invent an adjustable glass eye. are these the keys?"

"yes, sir. the large one belongs to the wicket in the front gate. the other is the latch-key belonging to the side door. mrs. shallybang has the key of the front door."

"thank you," said thorndyke. he took the keys, to which a wooden label was attached, and we made our way back towards the house of mystery, discussing the clerk's statements as we went.

"a very communicable young gentleman, that," thorndyke remarked. "he seemed quite pleased to relieve the monotony of office work with a little conversation. and i am sure i was very delighted to indulge him."

"he hadn't much to tell, all the same," said i.

thorndyke looked at me in surprise. "i don't know what you would have, jervis, unless you expect casual strangers to present you with a ready-made body of evidence, fully classified, with all the inferences and implications stated. it seemed to me that he was a highly instructive young man."

"what did you learn from him?" i asked.

"oh, come, jervis," he protested; "is that a fair question, under our present arrangement? however, i will mention a few points. we learn that about six or seven months ago, mr. h. weiss dropped from the clouds into kennington lane and that he has now ascended from kennington lane into the clouds. that is a useful piece of information. then we learn that mrs. schallibaum has remained in england; which might be of little importance if it were not for a very interesting corollary that it suggests."

"what is that?"

"i must leave you to consider the facts at your leisure; but you will have noticed the ostensible reason for her remaining behind. she is engaged in puttying up the one gaping joint in their armour. one of them has been indiscreet enough to give this address to some correspondent—probably a foreign correspondent. now, as they obviously wish to leave no tracks, they cannot give their new address to the post office to have their letters forwarded, and, on the other hand, a letter left in the box might establish such a connection as would enable them to be traced. moreover, the letter might be of a kind that they would not wish to fall into the wrong hands. they would not have given this address excepting under some peculiar circumstances."

"no, i should think not, if they took this house for the express purpose of committing a crime in it."

"exactly. and then there is one other fact that you may have gathered from our young friend's remarks."

"what is that?"

"that a controllable squint is a very valuable asset to a person who wishes to avoid identification."

"yes, i did note that. the fellow seemed to think that it was absolutely conclusive."

"and so would most people; especially in the case of a squint of that kind. we can all squint towards our noses, but no normal person can turn his eyes away from one another. my impression is that the presence or absence, as the case might be, of a divergent squint would be accepted as absolute disproof of identity. but here we are."

he inserted the key into the wicket of the large gate, and, when we had stepped through into the covered way, he locked it from the inside.

"why have you locked us in?" i asked, seeing that the wicket had a latch.

"because," he replied, "if we now hear any one on the premises we shall know who it is. only one person besides ourselves has a key."

his reply startled me somewhat. i stopped and looked at him.

"that is a quaint situation, thorndyke. i hadn't thought of it. why she may actually come to the house while we are here; in fact, she may be in the house at this moment."

"i hope not," said he. "we don't particularly want mr. weiss to be put on his guard, for i take it, he is a pretty wide-awake gentleman under any circumstances. if she does come, we had better keep out of sight. i think we will look over the house first. that is of the most interest to us. if the lady does happen to come while we are here, she may stay to show us over the place and keep an eye on us. so we will leave the stables to the last."

we walked down the entry to the side door at which i had been admitted by mrs. schallibaum on the occasion of my previous visits. thorndyke inserted the latch-key, and, as soon as we were inside, shut the door and walked quickly through into the hall, whither i followed him. he made straight for the front door, where, having slipped up the catch of the lock, he began very attentively to examine the letter-box. it was a somewhat massive wooden box, fitted with a lock of good quality and furnished with a wire grille through which one could inspect the interior.

"we are in luck, jervis," thorndyke remarked. "our visit has been most happily timed. there is a letter in the box."

"well," i said, "we can't get it out; and if we could, it would be hardly justifiable."

"i don't know," he replied, "that i am prepared to assent off-hand to either of those propositions; but i would rather not tamper with another person's letter, even if that person should happen to be a murderer. perhaps we can get the information we want from the outside of the envelope."

he produced from his pocket a little electric lamp fitted with a bull's-eye, and, pressing the button, threw a beam of light in through the grille. the letter was lying on the bottom of the box face upwards, so that the address could easily be read.

"herrn dr. h. weiss," thorndyke read aloud. "german stamp, postmark apparently darmstadt. you notice that the 'herrn dr.' is printed and the rest written. what do you make of that?"

"i don't quite know. do you think he is really a medical man?"

"perhaps we had better finish our investigation, in case we are disturbed, and discuss the bearings of the facts afterwards. the name of the sender may be on the flap of the envelope. if it is not, i shall pick the lock and take out the letter. have you got a probe about you?"

"yes; by force of habit i am still carrying my pocket case."

i took the little case from my pocket and extracting from it a jointed probe of thickish silver wire, screwed the two halves together and handed the completed instrument to thorndyke; who passed the slender rod through the grille and adroitly turned the letter over.

"ha!" he exclaimed with deep satisfaction, as the light fell on the reverse of the envelope, "we are saved from the necessity of theft—or rather, unauthorized borrowing—'johann schnitzler, darmstadt.' that is all that we actually want. the german police can do the rest if necessary."

he handed me back my probe, pocketed his lamp, released the catch of the lock on the door, and turned away along the dark, musty-smelling hall.

"do you happen to know the name of johann schnitzler?" he asked.

i replied that i had no recollection of ever having heard the name before.

"neither have i," said he; "but i think we may form a pretty shrewd guess as to his avocation. as you saw, the words 'herrn dr.' were printed on the envelope, leaving the rest of the address to be written by hand. the plain inference is that he is a person who habitually addresses letters to medical men, and as the style of the envelope and the lettering—which is printed, not embossed—is commercial, we may assume that he is engaged in some sort of trade. now, what is a likely trade?"

"he might be an instrument maker or a drug manufacturer; more probably the latter, as there is an extensive drug and chemical industry in germany, and as mr. weiss seemed to have more use for drugs than instruments."

"yes, i think you are right; but we will look him up when we get home. and now we had better take a glance at the bedroom; that is, if you can remember which room it was."

"it was on the first floor," said i, "and the door by which i entered was just at the head of the stairs."

we ascended the two flights, and, as we reached the landing, i halted.

"this was the door," i said, and was about to turn the handle when thorndyke caught me by the arm.

"one moment, jervis," said he. "what do you make of this?"

he pointed to a spot near the bottom of the door where, on close inspection, four good-sized screw-holes were distinguishable. they had been neatly stopped with putty and covered with knotting, and were so nearly the colour of the grained and varnished woodwork as to be hardly visible.

"evidently," i answered, "there has been a bolt there, though it seems a queer place to fix one."

"not at all," replied thorndyke. "if you look up you will see that there was another at the top of the door, and, as the lock is in the middle, they must have been highly effective. but there are one or two other points that strike one. first, you will notice that the bolts have been fixed on quite recently, for the paint that they covered is of the same grimy tint as that on the rest of the door. next, they have been taken off, which, seeing that they could hardly have been worth the trouble of removal, seems to suggest that the person who fixed them considered that their presence might appear remarkable, while the screw-holes, which have been so skilfully and carefully stopped, would be less conspicuous.

"then, they are on the outside of the door—an unusual situation for bedroom bolts—and were of considerable size. they were long and thick."

"i can see, by the position of the screw-holes, that they were long; but how do you arrive at their thickness?"

"by the size of the counter-holes in the jamb of the door. these holes have been very carefully filled with wooden plugs covered with knotting; but you can make out their diameter, which is that of the bolts, and which is decidedly out of proportion for an ordinary bedroom door. let me show you a light."

he flashed his lamp into the dark corner, and i was able to see distinctly the portentously large holes into which the bolts had fitted, and also to note the remarkable neatness with which they had been plugged.

"there was a second door, i remember," said i. "let us see if that was guarded in a similar manner."

we strode through the empty room, awakening dismal echoes as we trod the bare boards, and flung open the other door. at top and bottom, similar groups of screw-holes showed that this also had been made secure, and that these bolts had been of the same very substantial character as the others.

thorndyke turned away from the door with a slight frown.

"if we had any doubts," said he, "as to what has been going on in this house, these traces of massive fastenings would be almost enough to settle them."

"they might have been there before weiss came," i suggested. "he only came about seven months ago and there is no date on the screw-holes."

"that is quite true. but when, with their recent fixture, you couple the facts that they have been removed, that very careful measures have been taken to obliterate the traces of their presence, and that they would have been indispensable for the commission of the crime that we are almost certain was being committed here, it looks like an excess of caution to seek other explanations."

"but," i objected, "if the man, graves, was really imprisoned, could not he have smashed the window and called for help?"

"the window looks out on the yard, as you see; but i expect it was secured too."

he drew the massive, old-fashioned shutters out of their recess and closed them.

"yes, here we are." he pointed to four groups of screw-holes at the corners of the shutters, and, once more producing his lamp, narrowly examined the insides of the recesses into which the shutters folded.

"the nature of the fastening is quite evident," said he. "an iron bar passed right across at the top and bottom and was secured by a staple and padlock. you can see the mark the bar made in the recess when the shutters were folded. when these bars were fixed and padlocked and the bolts were shot, this room was as secure, for a prisoner unprovided with tools, as a cell in newgate."

we looked at one another for awhile without speaking; and i fancy that if mr. h. weiss could have seen our faces he might have thought it desirable to seek some retreat even more remote than hamburg.

"it was a diabolical affair, jervis," thorndyke said at length, in an ominously quiet and even gentle tone. "a sordid, callous, cold-blooded crime of a type that is to me utterly unforgivable and incapable of extenuation. of course, it may have failed. mr. graves may even now be alive. i shall make it my very especial business to ascertain whether he is or not. and if he is not, i shall take it to myself as a sacred duty to lay my hand on the man who has compassed his death."

i looked at thorndyke with something akin to awe. in the quiet unemotional tone of his voice, in his unruffled manner and the stony calm of his face, there was something much more impressive, more fateful, than there could have been in the fiercest threats or the most passionate denunciations. i felt that in those softly spoken words he had pronounced the doom of the fugitive villain.

he turned away from the window and glanced round the empty room. it seemed that our discovery of the fastenings had exhausted the information that it had to offer.

"it is a thousand pities," i remarked, "that we were unable to look round before they moved out the furniture. we might have found some clue to the scoundrel's identity."

"yes," replied thorndyke; "there isn't much information to be gathered here, i am afraid. i see they have swept up the small litter from the floor and poked it under the grate. we will turn that over, as there seems to be nothing else, and then look at the other rooms."

he raked out the little heap of rubbish with his stick and spread it out on the hearth. it certainly looked unpromising enough, being just such a rubbish heap as may be swept up in any untidy room during a move. but thorndyke went through it systematically, examining each item attentively, even to the local tradesmen's bills and empty paper bags, before laying them aside. another rake of his stick scattered the bulky masses of crumpled paper and brought into view an object which he picked up with some eagerness. it was a portion of a pair of spectacles, which had apparently been trodden on, for the side-bar was twisted and bent and the glass was shattered into fragments.

"this ought to give us a hint," said he. "it will probably have belonged either to weiss or graves, as mrs. schallibaum apparently did not wear glasses. let us see if we can find the remainder."

we both groped carefully with our sticks amongst the rubbish, spreading it out on the hearth and removing the numerous pieces of crumpled paper. our search was rewarded by the discovery of the second eye-piece of the spectacles, of which the glass was badly cracked but less shattered than the other. i also picked up two tiny sticks at which thorndyke looked with deep interest before laying them on the mantelshelf.

"we will consider them presently," said he. "let us finish with the spectacles first. you see that the left eye-glass is a concave cylindrical lens of some sort. we can make out that much from the fragments that remain, and we can measure the curvature when we get them home, although that will be easier if we can collect some more fragments and stick them together. the right eye is plain glass; that is quite evident. then these will have belonged to your patient, jervis. you said that the tremulous iris was in the right eye, i think?"

"yes," i replied. "these will be his spectacles, without doubt."

"they are peculiar frames," he continued. "if they were made in this country, we might be able to discover the maker. but we must collect as many fragments of glass as we can."

once more we searched amongst the rubbish and succeeded, eventually, in recovering some seven or eight small fragments of the broken spectacle-glasses, which thorndyke laid on the mantelshelf beside the little sticks.

"by the way, thorndyke," i said, taking up the latter to examine them afresh, "what are these things? can you make anything of them?"

he looked at them thoughtfully for a few moments and then replied:

"i don't think i will tell you what they are. you should find that out for yourself, and it will be well worth your while to do so. they are rather suggestive objects under the circumstances. but notice their peculiarities carefully. both are portions of some smooth, stout reed. there is a long, thin stick—about six inches long—and a thicker piece only three inches in length. the longer piece has a little scrap of red paper stuck on at the end; apparently a portion of a label of some kind with an ornamental border. the other end of the stick has been broken off. the shorter, stouter stick has had its central cavity artificially enlarged so that it fits over the other to form a cap or sheath. make a careful note of those facts and try to think what they probably mean; what would be the most likely use for an object of this kind. when you have ascertained that, you will have learned something new about this case. and now, to resume our investigations. here is a very suggestive thing." he picked up a small, wide-mouthed bottle and, holding it up for my inspection, continued: "observe the fly sticking to the inside, and the name on the label, 'fox, russell street, covent garden.'"

"i don't know mr. fox."

"then i will inform you that he is a dealer in the materials for 'make-up,' theatrical or otherwise, and will leave you to consider the bearing of this bottle on our present investigation. there doesn't seem to be anything else of interest in this el dorado excepting that screw, which you notice is about the size of those with which the bolts were fastened on the doors. i don't think it is worth while to unstop any of the holes to try it; we should learn nothing fresh."

he rose, and, having kicked the discarded rubbish back under the grate, gathered up his gleanings from the mantelpiece, carefully bestowing the spectacles and the fragments of glass in the tin box that he appeared always to carry in his pocket, and wrapping the larger objects in his handkerchief.

"a poor collection," was his comment, as he returned the box and handkerchief to his pocket, "and yet not so poor as i had feared. perhaps, if we question them closely enough, these unconsidered trifles may be made to tell us something worth learning after all. shall we go into the other room?"

we passed out on to the landing and into the front room, where, guided by experience, we made straight for the fire-place. but the little heap of rubbish there contained nothing that even thorndyke's inquisitive eye could view with interest. we wandered disconsolately round the room, peering into the empty cupboards and scanning the floor and the corners by the skirting, without discovering a single object or relic of the late occupants. in the course of my perambulations i halted by the window and was looking down into the street when thorndyke called to me sharply:

"come away from the window, jervis! have you forgotten that mrs. schallibaum may be in the neighbourhood at this moment?"

as a matter of fact i had entirely forgotten the matter, nor did it now strike me as anything but the remotest of possibilities. i replied to that effect.

"i don't agree with you," thorndyke rejoined. "we have heard that she comes here to look for letters. probably she comes every day, or even oftener. there is a good deal at stake, remember, and they cannot feel quite as secure as they would wish. weiss must have seen what view you took of the case and must have had some uneasy moments thinking of what you might do. in fact, we may take it that the fear of you drove them out of the neighbourhood, and that they are mighty anxious to get that letter and cut the last link that binds them to this house."

"i suppose that is so," i agreed; "and if the lady should happen to pass this way and should see me at the window and recognize me, she would certainly smell a rat."

"a rat!" exclaimed thorndyke. "she would smell a whole pack of foxes, and mr. h. weiss would be more on his guard than ever. let us have a look at the other rooms; there is nothing here."

we went up to the next floor and found traces of recent occupation in one room only. the garrets had evidently been unused, and the kitchen and ground-floor rooms offered nothing that appeared to thorndyke worth noting. then we went out by the side door and down the covered way into the yard at the back. the workshops were fastened with rusty padlocks that looked as if they had not been disturbed for months. the stables were empty and had been tentatively cleaned out, the coach-house was vacant, and presented no traces of recent use excepting a half-bald spoke-brush. we returned up the covered way and i was about to close the side door, which thorndyke had left ajar, when he stopped me.

"we'll have another look at the hall before we go," said he; and, walking softly before me, he made his way to the front door, where, producing his lamp, he threw a beam of light into the letter-box.

"any more letters?" i asked.

"any more!" he repeated. "look for yourself."

i stooped and peered through the grille into the lighted interior; and then i uttered an exclamation.

the box was empty.

thorndyke regarded me with a grim smile. "we have been caught on the hop, jervis, i suspect," said he.

"it is queer," i replied. "i didn't hear any sound of the opening or closing of the door; did you?"

"no; i didn't hear any sound; which makes me suspect that she did. she would have heard our voices and she is probably keeping a sharp look-out at this very moment. i wonder if she saw you at the window. but whether she did or not, we must go very warily. neither of us must return to the temple direct, and we had better separate when we have returned the keys and i will watch you out of sight and see if anyone is following you. what are you going to do?"

"if you don't want me, i shall run over to kensington and drop in to lunch at the hornbys'. i said i would call as soon as i had an hour or so free."

"very well. do so; and keep a look-out in case you are followed. i have to go down to guildford this afternoon. under the circumstances, i shall not go back home, but send polton a telegram and take a train at vauxhall and change at some small station where i can watch the platform. be as careful as you can. remember that what you have to avoid is being followed to any place where you are known, and, above all, revealing your connection with number five a, king's bench walk."

having thus considered our immediate movements, we emerged together from the wicket, and locking it behind us, walked quickly to the house-agents', where an opportune office-boy received the keys without remark. as we came out of the office, i halted irresolutely and we both looked up and down the lane.

"there is no suspicious looking person in sight at present," thorndyke said, and then asked: "which way do you think of going?"

"it seems to me," i replied, "that my best plan would be to take a cab or an omnibus so as to get out of the neighbourhood as quickly as possible. if i go through ravensden street into kennington park road, i can pick up an omnibus that will take me to the mansion house, where i can change for kensington. i shall go on the top so that i can keep a look-out for any other omnibus or cab that may be following."

"yes," said thorndyke, "that seems a good plan. i will walk with you and see that you get a fair start."

we walked briskly along the lane and through ravensden street to the kennington park road. an omnibus was approaching from the south at a steady jog-trot and we halted at the corner to wait for it. several people passed us in different directions, but none seemed to take any particular notice of us, though we observed them rather narrowly, especially the women. then the omnibus crawled up. i sprang on the foot-board and ascended to the roof, where i seated myself and surveyed the prospect to the rear. no one else got on the omnibus—which had not stopped—and no cab or other passenger vehicle was in sight. i continued to watch thorndyke as he stood sentinel at the corner, and noted that no one appeared to be making any effort to overtake the omnibus. presently my colleague waved his hand to me and turned back towards vauxhall, and i, having satisfied myself once more that no pursuing cab or hurrying foot-passenger was in sight, decided that our precautions had been unnecessary and settled myself in a rather more comfortable position.